1. Technical Field
This document relates to methods and materials involved in making and using growth factors, chemokines, and molecules responsible for growing, differentiating, or maintaining undifferentiated cells from normal human platelets (e.g., platelet lysates). For example, this document relates to methods and materials for manufacturing from platelets or platelet preparations (e.g., platelet apheresis preparations) those factors used to grow stem cells (e.g., adult stem cells) rapidly, to maintain them in an undifferentiated form, as an additive to media to differentiate stem cells (e.g., adult stem cells) in combination with other factors, to grow primary cell cultures (e.g., tumor cells and tumor cell lines), and to grow tumor cells with stem cell properties. This document also relates to methods and materials that can be used to identify, isolate, enrich, or optimize combinations of effective growth factors using platelets as a source material. In addition, the document relates to platelet plasma culture supplements and compositions containing platelet contents.
2. Background Information
Cell culture is involved in much of modern biology, drug discovery, and therapy. For example, primary tumor cells can be cultured to obtain an antigen source that can be used in anti-tumor vaccines. Two general methods are used to culture primary brain tumor cells. Traditionally, cells are grown in minimal media supplemented with fetal bovine serum. Cells grown in this way can exhibit limited applicability as an effective antigen source because they often exhibit characteristics of differentiated glial cell subtypes with a reduced ability to recapitulate the original tumor in vivo. Alternatively, cells can be grown in an enriched media supplemented with growth factors, EGF, and FGF. Cells grown in this environment can form neurospheres and can contain populations of tumor stem cells, which more closely recapitulate the phenotypic characteristics of the primary tumor. Although these cells can have reduced proliferative capacities, they are typically less differentiated, more tumorigenic, and more antigenic than cells grown in fetal bovine serum (Lee et al., Cancer Cell., 9:391-403 (2006)). These approaches do not appear to generate primary tumor cultures with high efficiencies and do not appear to allow for the growth of cultures fast enough for many applications. While these methods can be used to generate cell cultures from malignant gliomas, these protocols typically include materials and methods not suitable for clinical use.